This invention relates generally to environmentally controlled testing chambers, and in particular, to an environmentally controlled testing chamber which incorporates electromagnetic and radio frequency wave shielding of the interior thereof.
Many types of electronic and wireless devices undergo testing to improve the overall quality and reliability of the devices. Typically, these types of electronic and wireless devices undergo a series of environmental tests under various combinations of temperature, humidity, and other climatic conditions to insure product reliability and performance at extreme environmental conditions. Further, many of such devices are tested to insure that the devices are not adversely affected when a plurality of such devices are used in a common environment.
In order to test their electronic and wireless devices, manufactures often utilize environmental testing chambers which are capable of producing rapid and extreme changes in temperature, humidity and other climatic conditions. A prominent designer and manufacture of such environmental testing chambers is Thermotron Industries, Inc., of Holland, Mich.
The climatic conditions within the environmental testing chamber are controlled by heating, humidity and air conditioning units which generate the rapid changes in climatic conditions within the test chamber. However, these units could possibly generate electromagnetic and radio frequency waves which may adversely affect the testing of the electronic and wireless devices in the environmental testing chamber. Likewise, many electronic and wireless devices generate their own electromagnetic and radio frequency waves during operation and/or testing. Due to the large number of devices which are tested simultaneously in the environmental testing chamber, individuals in proximity to the environmental testing chamber may be exposed to the cumulative electromagnetic and radio frequency waves generated by the devices.
Heretofore, in order to minimise the effects of the electromagnetic and radio frequency waves emanating from an environmental testing chamber during testing of electronic and wireless devices, a screened enclosure is built around the entire environmental testing chamber in order to isolate the testing chamber from the surrounding environment. Not only does such an enclosure occupy a substantial amount of floor space in the testing facility, but also traps heat generated by the test chamber therein. This, in turn, may result in a uncomfortable working environment for the operators conducting the desired testing and increases the stress on the equipment within the screened enclosure.
Therefore, it is a primary object and feature of the present invention to provide an environmental testing chamber for testing products under various climatic conditions.
It is a further object and feature of the present invention to provide an environmental testing chamber which limits electromagnetic and radio frequency waves from entering and/or exiting the interior cavity of the environmental testing chamber.
It is a still further object and feature of the present invention to provide an environmental testing chamber which is simple and less expensive to manufacture.
It is a still further object and feature of the present invention to provide an environmental test chamber which reduces the effects of electromagnetic and radio frequency waves emanating therefrom during the testing of electronic and wireless devices.
In accordance with the present invention, an apparatus is provided for conducting environmental tests on a device. The apparatus includes a cabinet defining a testing chamber for receiving the device therein. A control structure is interconnected the cabinet for varying environmental conditions within the testing chamber to a user desired environment. Isolation structure provides a barrier between the device and the control structure.
The isolation structure may include an enclosure which surrounds the device. The enclosure is receivable within the testing chamber and is formed from electromagnetic wave absorbing material and/or a radio wave absorbing material. The enclosure includes a plurality of openings therein so as to allow for the flow of air therethrough.
Alternatively, it is contemplated that the isolation structure include a shield positioned between the control structure and the device. The shield may be formed from an electromagnetic wave absorbing and/or a radio wave absorbing material. Openings are provided in the shield to allow for the flow of air therethrough.
A thermocouple extends into the testing chamber for monitoring the temperature therein. The thermocouple is partially surrounded by an isolation tube to limit any electromagnetic and/or radio frequency waves radiating from the thermocouple from entering the testing chamber. The isolation tube of the thermocouple includes a first layer for preventing electromagnetic waves from passing therethrough and a second outer layer. It is contemplated the inner layer be formed from plurality of ferrite sections.
In accordance with a still further aspect of the present invention, an apparatus is provided for conducting an environmental test on a device. The apparatus includes a cabinet which defines a testing chamber for receiving the device therein. A door is pivotably mounted to the cabinet and movable between a first open position allowing access to the interior of the testing chamber and a second closed position wherein access to the testing chamber is prevented. Door sealing structure is provided for sealing the intersection of the door and the cabinet when the door is in the closed position. Control structure operatively connected to the cabinet varies the environmental conditions within the testing chamber to a user desired environment. An isolation structure isolates the device from the control structure by limiting predetermined waves from passing therethrough.
It is contemplated that the isolation structure include a shield positioned within the testing chamber between the control structure and the device. It is contemplated for the shield to surround the entire device. The shield is formed from a electromagnetic wave absorbing material and/or a radio wave absorbing material. A plurality of passages arranged in a honeycomb configuration in the shield allow for the flow of air therethrough. A sealing structure is provided about the outer periphery of the shield so as to prevent electromagnetic and radio frequency waves from traveling therepast.